Figure 12.11 shows an example of an SCI receive operation using a multiprocessor format (8-bit
data with multiprocessor bit and one stop bit).
Start
bit
Stop Start
MPB bit bit
Stop
MPB bit
Data (ID1)
D0 D1
Data (Data1)
D0 D1 D7
1
1
0
D7
1
1
0
0
1
Idle state
(mark)
MPIE
RDRF
RDR value
ID1
MPB detection RXI request RXI handler reads
Not own ID, so No RXI request,
MPIE = 0
RDR data and clears MPIE is set to RDR not updated
RDRF to 0
(Multiprocessor interrupt)
1 again
(a) Own ID does not match data
Start
bit
Stop Start
MPB bit bit
Stop
MPB bit
Data (ID2)
D0 D1
Data (Data2)
D0 D1 D7
1
1
0
D7
1
1
0
0
1
Idle state
(mark)
MPIE
RDRF
RDR value
ID2
Data 2
MPB detection RXI request
MPIE = 0
RXI handler reads
RDR data and clears continues, with data
RDRF to 0 received at each RXI
Own ID, so receiving MPIE set to
1 again
(Multiprocessor interrupt)
(b) Own ID matches data
Figure 12.11 Example of SCI Receive Operation
(8-Bit Data with Multiprocessor Bit and One Stop Bit)
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HITACHI [ HITACHI SEMICONDUCTOR ]
